One method of transporting liquids, such as liquid chemicals or liquids for human consumption, is to load the liquids into a shipping container, such as a cylindrical tank mounted in a rectangular frame. When filled, such a shipping tank or tank container can be transported by truck to a port and then loaded on, for example, a container ship for transoceanic transport to another port. The tank container is unloaded from the container ship at the destination port and is emptied of its liquid cargo. The tank container may then be re-used for transporting another liquid cargo, provided such a cargo is available and provided the tank container is in a condition for receiving another cargo. Having a tank container in a condition for receiving another cargo typically involves cleaning the tank at a cleaning station specifically designed for such a purpose. Cleaning a tank container is a relatively expensive process. To avoid or minimize such cleaning, a flexible liner may be installed in the tank.